Due to the popularity of the use of Radio Frequency Identification (RFID) readers in Physical Access Control Systems (PACS) and the difficulty in making credentials secure from being stolen, lost, cloned, etc., there is a real need to use additional factors of authentication. The axiom of something you have, something you know, and something you are has traditionally been used to increase the security of a PACS employing machine-readable credential technologies such as RFID, magnetic stripe, bar code, Wiegand, and others. The more “factors” of authentication that are utilized, the higher the confidence that the person presenting the credential is actually the person to whom the credential was originally issued.
Traditionally, a biometric reader has been deployed to acquire a second factor of authentication representing “something you are”. While biometric readers are useful for increasing the security of a PACS, deployment of a biometric reader is more costly than the use of, for example, a keypad to query the user as to “something you know”.